公开(公告)号：CA1124877A

公开(公告)日：1982-06-01

申请号：CA345521

申请日：1980-02-12

Applicant: IBM

Inventor： HOWELL DAN M ,  KOLPEK ROBERT A ,  SCHULLER WILLIAM M

IPC: H04M11/10 ,  G06F3/023 ,  G06F3/048 ,  H04L29/00 ,  H04M11/00 ,  H04M11/06 ,  G11B31/00 ,  G06F1/00

Abstract: A COMMUNICATING TYPEWRITER AND DICTATION SYSTEM UTILIZING ANALOG RECORDING AND TRANSMISSION TECHNIQUES A combined communicating typewriter/dictation system which utilizes a common modem as an interface between an electronic typewriter, a mass media recorder and a communications line. The modem replaces digital logic and audio tones are recorded on the mass media recorder instead of digital tones. When the system is in a local mode the digital keystroke signals from the typewriter are modulated by the modem and recorded by the mass media recorder. In a communications mode the recorded keystroke signals are demodulated and then remodulated before transmission over the communications line to eliminate noise and other extraneous signals that tend to increase the error rate of the transmitted signals. When data is received by the system for storage on the mass media recorder, the transmitted data is demodulated and then remodulated by the modem to eliminate noise from the transmitted signal. In both communication paths the analog signal input to the modem is processed twice before it is either forwarded to the mass media recorder or to the communications line. In addition to the foregoing recording functions, the mass media recorder can also be utilized to record and/or playback audio information. The dual utilization of the modem and the mass media recorder results in a low cost system without sacrificing much in the way of recording error rate. LE9-78-024